One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of getting a good idea when it's a good idea to plant bougainvillea is to consult the USDA zone info for Thornton.

Planting Calendar for Bougainvillea

Frost tolerance for bougainvillea:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's not a good idea to plant bougainvillea until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant bougainvillea in Thornton is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant bougainvillea and expect a good harvest is probably August. If you wait any later than that and your bougainvillea may not have a chance to fully mature. If you are starting your bougainvillea indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Thornton. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Thornton may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Thornton you get surprised by a frost after April 15 so make sure that you are ready to protect your bougainvillea if you have one of those late frosts.

USDA Zone Info for Thornton

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Thornton

You may be interested in your other planting guides for Thornton.